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TAPPER: Thanks for watching.

[17:00:06] WOLF BLITZER, CNN ANCHOR: Breaking news. The Kim Jong-un regime accuses the U.S. of pushing the Korean Peninsula toward a military conflict and vows revenge for tough new U.N. sanctions. North Korea says it will never negotiate over its nuclear program, leaving Washington and Pyongyang in a high-stakes standoff.

Tweet escape. President Trump's vacation doesn't include time off from Twitter, with the president unleashing a tweet storm against the Democratic senator over his comments on the Russia investigation, including a tweet just moments ago. I'll talk to the target of the president's tirade this hour.

Filling the void. Secretary of State Rex Tillerson says what President Trump won't, warning Moscow that its election meddling has hurt U.S.-Russia relations. With the Kremlin now expelling U.S. diplomats in retaliation for new U.S. sanctions, how will the Trump administration respond?

And Pence's protest. Vice President Mike Pence forcefully puts down a report that he's looking at a White House bid if President Trump doesn't run again in 2020. Pence calls the story, quote, "disgraceful and offensive." Why is he responding so aggressively?

I'm Wolf Blitzer. You're in THE SITUATION ROOM.

Any hopes that recent White House shake-ups might tame President Trump's use of Twitter are being proved false. The president tweeted a tirade, including one just moments ago against Democratic Senator Richard Blumenthal, who he's targeted previously and will join us shortly to talk about the president's attacks and the Russia investigation.

Meanwhile, Deputy Attorney General Rod Rosenstein is defending the probe, saying it's not a fishing expedition as critics have charged. With the investigation now said to have expanded to include possible Trump financial ties to Russia, Rosenstein said Special Counsel Robert Mueller can enlarge the scope of his probe, if it's deemed appropriate.

And North Korea is vowing the U.S. will pay dearly for tough new sanctions approved by the United Nations as punishment for Pyongyang's increasingly aggressive missile program. Secretary of State Rex Tillerson suggested conditional talks with the Kim regime, but North Korea says it won't negotiate on its nuclear and missile programs under any circumstances.

We're covering all of that and much more this hour with our guests, including Senator Richard Blumenthal of the Judiciary Committee, who was attacked by President Trump once again only moments ago on Twitter. And our correspondents and specialists are also standing by.

Let's begin with President Trump's on-line fuming at Senator Blumenthal and others. Our senior White House correspondent, Jim Acosta, is here with the very latest. Jim, this isn't the first time the president has targeted this senator.

JIM ACOSTA, CNN SENIOR WHITE HOUSE CORRESPONDENT: That's right, not the first time; probably not the last, Wolf. President Trump is trying to make it clear he is not on vacation these next two weeks. He's certainly not taking a break from social media. The president was back to tweeting his inner monologue with a vengeance, unleashing his vitriol on some familiar targets.

(BEGIN VIDEOTAPE)

ACOSTA (voice-over): From his golf club in New Jersey, President Trump is teeing off on Twitter, slamming Connecticut Democratic Senator Richard Blumenthal tweeting, "Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist."

SEN. RICHARD BLUMENTHAL (D), CONNECTICUT: I am proud...

ACOSTA: The president blasted Blumenthal, who once acknowledge he misled voters about his military service during the Vietnam war, about the senator raised questions on CNN about the Trump administration's hunt for leakers in the Russia probe.

BLUMENTHAL: Politicizing the Department of Justice for personal ends, I think, is a disservice to the law; and it's also potentially a violation of the spirit of the First Amendment. Remember, what we know about the Trump administration so far has been the result of very good reporting.

ACOSTA: After Blumenthal's interview, the president, who once received five military draft deferments during the Vietnam War, went on a tirade, tweeting, "Never in U.S. history has anyone lied or defrauded voters like Senator Richard Blumenthal. He told stories about his Vietnam battles and conquests, how brave he was, and it was all a lie. He cried like a baby and begged for forgiveness like a child. Now he judges collusion?"

Blumenthal fired back, "Mr. President, your bullying hasn't worked before, and it won't work now. No one is above the law."

The president is also lashing out at the news media, tweeting, "Hard to believe that, with 24/7 fake news on CNN, ABC, NBC, CBS, 'New York Times,' and 'Washington Post,' the Trump base is getting stronger." The tweet storm raises new questions about whether chief of staff John

Kelly can truly bring discipline to the White House. Then again, Kelly once joked the president could use a ceremonial sword on the news media.

JOHN KELLY, WHITE HOUSE CHIEF OF STAFF: Use that on the press, Sir. Use that on the press.

DONALD TRUMP (R), PRESIDENT OF THE UNITED STATES: Yes.

ACOSTA: The president's family is joining his crusade against the press.

LARA TRUMP, DONALD TRUMP'S DAUGHTER-IN-LAW: I bet you haven't heard about all the accomplishments the president had this week, because there is so much fake news out there.

ACOSTA: With the president's approval numbers plunging in recent weeks, he has focused on energizing his core of supporters, tweeting, "The Donald Trump base is far bigger and stronger than ever before, despite some fake news polling. Look at rallies in Pennsylvania, Iowa, Ohio."

But there is reason for the president to worry, as a recent Quinnipiac poll found a key voting bloc for Mr. Trump, white voters without a college degree, now disapprove of the job he's doing.

CONWAY: His approval rating among Republicans and conservative and Trump voters is down slightly. It needs to go up. They are telling him, just enact your program.

MIKE PENCE (R), VICE PRESIDENT OF THE UNITED STATES: Have faith in this president.

ACOSTA: Another potential warning sign: a "New York Times" report that allies of Vice President Pence are quietly laying the groundwork for 2020. But both the White House and Pence's spokesperson are adamant that such talk is fake news.

MARC LOTTER, VICE PRESIDENT'S PRESS SECRETARY: We are all operating under the assumption every day that the president is seeking reelection in 2020.

(END VIDEOTAPE)

ACOSTA: Despite the backlash against his social media habits, the president is determined to keep on tweeting. Still, the public has lost nearly all patience with this. The respected Quinnipiac polling unit found 69 percent of American voters say the president should stop tweeting from his personal account. And Wolf, earlier this afternoon, the president accused the media of ignoring these new sanctions on North Korea. That's obviously false. Not only is he annoying his base and many Americans out there, he's misleading them, as well.

The deputy attorney general, Rod Rosenstein, is defending the special counsel's Russia investigation, which sources say has now spread to possible financial ties between the president, his associates and Russia.

Let's go to our justice correspondent, Jessica Schneider, who's working the story for us. Jessica, Rosenstein also said the special counsel, Robert Mueller, can investigate any potential crimes he uncovers.

JESSICA SCHNEIDER, CNN JUSTICE CORRESPONDENT: Yes, that's right, Wolf. Rosenstein said that Mueller can expand his probe if he uncovers over crimes in the course of the investigation. Of course, after all, the special counsel order signed by Rosenstein back in May, it allows Mueller to delve into any matters that, quote, "arose or may arise directly from the investigation."

CNN has already reported that the investigation has widened to focus on possible financial crimes and President Trump and his associate's ties to Russia.

Now, the president did say in a "New York Times" interview that his business dealings were out of bounds for Mueller, saying it would cross a red line. And, of course, President Trump has repeatedly taken to Twitter to denounce the investigation as a, quote, "witch hunt," today even tweeting it was, quote, "fake news." But Deputy Attorney General Rosenstein pushed back hard on those characterizations.

(BEGIN VIDEO CLIP)

ROD ROSENSTEIN, DEPUTY ATTORNEY GENERAL: The special counsel is subject to the rules and regulations of the Department of Justice, and we don't engage in fishing expeditions.

If he finds evidence of a crime that's within the scope of what Director Mueller and I have agreed is the appropriate scope in this investigation, then he can. If it's something outside that scope, he needs to come to the acting attorney general, at this time me, for permission to expand his investigation.

(END VIDEO CLIP)

SCHNEIDER: And we know that Mueller has already been moving forward, using a grand jury to issue subpoenas related to Donald Trump Jr.'s 2016 meeting with a Russian lawyer at Trump Tower. That's according to sources. And Republican Senator Tom Tillis on the Senate Judiciary Committee has warned the president against any move to fire Mueller. Tillis has even co-sponsored legislation that would bar the president from directly firing any special counsel -- Wolf.

Let's gets some more on all of this. Democratic Senator Richard Blumenthal of Connecticut is joining us. He's a member of the Judiciary Committee. This is his first interview since President Trump's series of online attacks against him.

Senator, thanks for joining us.

BLUMENTHAL: Thank you, Wolf. Good to be with you.

BLITZER: All right. So just moments ago, just before we went on the air, the president tweeted this about you, and I'll put it up on the screen. "I think Senator Blumenthal should take a nice, long vacation in Vietnam where he lied about his service, so he can at least say he was there."

And earlier in the day, he also had a series of tweets involving you. Let me read them to our viewers at the same time. "Interesting to watch Senator Richard Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist. Never in U.S. history has anyone lied or defrauded voters like Senator Richard Blumenthal. He told stories about his Vietnam battles and conquests, how brave he was, and it was all a lie. He cried like a baby and begged for forgiveness like a child. Now he judges collusion."

All right. This is your chance to respond to those series of attacks on Twitter by the president.

[17:10:02] BLUMENTHAL: There is an ongoing special counsel investigation. It is real. It is based on facts. That's what is important. That focus is what really matters. Our national security and the rule of law are at risk, and that's where our focus should be. It is not about me.

BLITZER: But he goes after you over and over again. This isn't the first time. We checked. In February of this year, he said, "Senator Richard Blumenthal, who never fought in Vietnam, and he said for years he had. Major lie. Now misrepresents what Judge Gorsuch told him."

In May of this year, "Watching Senator Richard Blumenthal speak of Comey as a joke. Richie devised one of the greatest military frauds in U.S. history."

Is there something personal about his relationship with you that you know about? Because a lot of people criticize him; he doesn't go after him the way he goes after you.

BLUMENTHAL: I have no idea about what is in his mind. What I do know is I will not be distracted by this bullying. And these bullying tweets reinforce for me the need for a piece of legislation that I am helping to lead with Tom Tillis and others, bipartisan coalition, to prevent firing of the special counsel Robert Mueller, whom he has also sought so intimidate.

And the kinds of statements we've seen about drawing red lines around financial dealings, about calling the investigation a witch hunt or a hoax, and the attacks on the team that Robert Mueller has assembled all point to a looming constitutional crisis if the president proceeds with firing Robert Mueller. And that's why preventing it, forstalling that kind of constitutional conflagration, is the objective of a group of us, a bipartisan coalition, including both Republican and Democrat colleagues who are intent on sending a message that the rule of law will prevail, and no one is above the rule of law, including the president.

BLITZER: I assume, Senator, you've seen the reports out that, for some reason, your father-in-law and Donald Trump and his company competed in various real estate deals, big building deals, including the Empire State Building im New York city and there's a personal animosity there. What can you tell us, if anything, about that?

BLUMENTHAL: It is not about me. It is about upholding the rule of law and protecting our national security and making sure the independence on integrity of this special counsel legislation is really the uppermost goal in my mind. And we are taking steps to make sure there are colleagues who are better informed about the threats to the independence and the integrity of this investigation.

The grand jury that has recently been reported is a stuff towards giving us an arm of the court as well as an investigative tool. And the president of the United States can take the extreme step and egregious step of trying to fire the special counsel, but he can't fire the grand jury or the United States district court that impaneled it.

BLITZER: I want to get on to some other issues, but I don't know if the president is watching or not watching right now. But do you want to respond? Do you want to say anything directly to the president about the series of attacks he's now leveling against you, your experience in the U.S. Marine Corps -- Marine Corps Reserves during the Vietnam War. We know you didn't serve in Vietnam. He makes a big deal out of it. Is there anything you would want to say to him?

BLUMENTHAL: All I would say is that let's protect the independence and integrity of the special counsel who is investigating Russian interference in our 2016 election, possible collusion and conspiracy involving the Trump campaign, and allegations of obstruction of justice afterward. That work is paramount in importance. It really is not about me.

BLITZER: The deputy attorney general, Rod Rosenstein, said over the weekend that the Robert Mueller investigation was not a fishing expedition. I assume you were encouraged by his comments, as opposed to what the president is saying?

BLUMENTHAL: I was encouraged by the comments by Deputy Attorney General Rosenstein that he's convinced there's no fishing expedition here. In fact, the special counsel has a very broad mandate. And it includes financial dealings by the president. We know that one of the elements of the Russian playbook is to enlist and engage and possibly entangle foreign officials in financial dealings. And we have seen from the financial dealings of Michael Flynn how that can work. So this kind of investigation, far from being a witch hunt, is a legitimate and ongoing investigation. It is real. It is based on facts.

BLITZER: Because Rod Rosenstein, the deputy attorney general, he named Robert Mueller to become the special counsel. As you know, the president hasn't hesitated to criticize Rosenstein, among others.

Do you think that the president actually would fire Rosenstein?

BLUMENTHAL: There are a lot of ominous indications. The kinds of threats and bullying that we've seen, publicly. Some reported privately. We know about them because of reporting, excellent reporting. And the threats now to try to restrict that reporting all are extremely concerning.

And so the idea of a three-judge panel, as we suggested in our legislation, or actually two pieces of legislation, and they're virtually identical, would provide a check. Our system survives and thrives because of checks and balances. And a judicial check on presidential abuse of power is very well-warranted here to send a message that the Congress and the judiciary will provide a check on any firing of Robert Mueller, because his investigation must proceed, and it will proceed.

BLITZER: All right, Senator. There's more we need discuss. I've got to take a quick break. We'll resume this interview right after this.

(COMMERCIAL BREAK)

[17:21:21] BLITZER: We're back with Senator Richard Blumenthal of Connecticut. He was attacked repeatedly today by President Trump on Twitter. We're going to talk to him about that and more. Also discuss some tough new talk coming from North Korea right now, which is blasting new United Nations sanctions and warning it will make the United States pay dearly.

Senator, I want you to stand by.

I want to quickly go to CNN's Brian Todd, who's got the very latest for us.

Brian, North Korea's foreign minister says that under no circumstances whatsoever will North Korea negotiate with the United States or anyone else over its nuclear weapons program.

BRIAN TODD, CNN CORRESPONDENT: He did say that, Wolf, repeating North Korea's stance that it needs its nuclear weapons to counter the military threat that it sees from America.

Tonight, we're at a critical moment with North Korea. There is an opening for diplomacy to steer us away from the nuclear missile standoff, but at the same time, Kim Jong-un's regime is vowing revenge against the United States for leading the way with new sanctions against Pyongyang.

Tonight, the key question is, which way is this going to break?

(BEGIN VIDEOTAPE)

TODD (voice-over): From Kim Jong-un, biting insults. His regime referring to the U.S. as, quote, "gangsters" and a threat from one of his news anchors.

UNIDENTIFIED FEMALE (through translator): There is no bigger mistake than the United States believing that its land is safe across the ocean.

TODD: Kim's regime is lashing out at the U.S. for pushing through a tough new round of economic sanctions from the United Nations against Pyongyang, choking off North Korea's coal, iron and other exports. After leading that charge, Ambassador Nikki Haley talked even tougher on CNN.

NIKKI HALEY, U.S. AMBASSADOR TO U.N.: We're prepared to do whatever it takes to defend ourselves and to defend our allies. We have tried to say multiple times that all options are on the table.

TODD: Among those options, so-called preventive war, according to President Trump's national security adviser, H.R. McMaster. But at the same time, the president's chief diplomat signals a potential opening.

REX TILLERSON, SECRETARY OF STATE: The best signal that North Korea could give us that they're prepared to talk would be to stop these missile launches.

TODD: That appears to inch back from America's long-held stance that the U.S. would only negotiate with North Korea if Pyongyang abandons its nuclear program.

ABRAHAM DENMARK, FORMER DEPUTY ASSISTANT SECRETARY OF DEFENSE: I think it makes sense to have that negotiation, and to allow for those conditions to happen. The challenge, though, from what we've seen is that North Korea has not given us any indication that they're actually interested in talking to us right now.

TODD: Analysts say the hard line from one side of Trump's administration with a softer approach from the other is a carrot and stick tactic to get North Korea's dictator to stop acting so aggressively.

PATRICK CRONIN, CENTER FOR NEW AMERICAN SECURITY: You can see the dual track, defense and hard line coercive pressure on the one hand, and diplomacy and engagement on the other hand. We're trying to bring North Korea back to the negotiating table.

TODD: But experts say that could be a risky move, depending on how Kim Jong-un reads it.

DENMARK: For our adversaries, they may see that the United States is uncoordinated, doesn't have a plan, and is not really committed to this issue. For our allies, they may see that the United States doesn't really have a plan, is not necessarily committed to this, and may act in ways that they would not be comfortable with.

(END VIDEOTAPE)

TODD: The concern tonight is is all this diplomatic jockeying at such a critical moment might lead Kim Jong-un or President Trump or one of America's allies in the region to miscalculate, take a certain signal the wrong way and launch a military action that might make things here spiral out of control, Wolf.

BLITZER: Brian, Ambassador Nikki Haley, the U.S. ambassador to the U.N., says these sanctions will be, in her words, a gut punch to the Kim Jong-un regime. What are experts saying tonight about the new sanctions, the U.N. Security Council sanctions, and whether they'll be successful in getting North Korea to back off its nuclear and missile programs?

[17:25:04] TODD: Wolf, tonight most experts saying these new sanctions are not likely to get the regime to back off that weapons program. One analyst says this regime has a history going back to before the Korean War of being able to weather almost any kind of economic pressure. He says North Korea is, quote, "good at taking pain." They just channel all that toward their citizens, and they -- you know, they get -- they find a way around these sanctions.

BLITZER: Brian Todd reporting for us. Thank you.

We're talking with Democratic Senator Richard Blumenthal, a member of both the Judiciary and Armed Services Committee.

Senator, you just heard North Korea saying the U.S. is driving the Korean Peninsula to war. How should the U.S. proceed right now? Could all of this lead to a confrontation?

BLUMENTHAL: It could well lead to a confrontation, either as a result of miscalculation or simply the North Koreans testing us. But there ought to be agreement, and it should be bipartisan agreement, that the sanctions now have to be vigorously and strenuously enforced through a multi-national effort.

The emissaries of the United States should be going around the world, just as was done with Iran, and eventually Iran was brought to the table. That kind of full-court press is what the Australians and Japanese have recommended and what we now have to do. Because these sanctions affect one-third of North Korean's exports. The focus should be particularly on financial institutions. Money is the lifeblood of the North Korean regime.

If we say to banks in China and elsewhere, "You have to choose. Either deal with the North Koreas or deal with us. You can't do both."

BLITZER: Well, clearly, China, the main exporter/importer involving North Korea, is key to all this. Do you believe that China will get the job done and do what they're supposed to do?

BLUMENTHAL: If more pressure, particularly financially, is brought on China, it is the best hope we have to avoid any military option, certainly diplomacy ought to be our first and second resort. And so we have to invest as heavily as we can in pressuring China to do the right thing, not only on the financial institutions but also in the use of North Korean labor and other areas where it has been reluctant to cooperate.

BLITZER: This weekend the U.S. ambassador to the U.N., Nikki Haley, said the U.S. is prepared to do, quote, "whatever it takes" when it comes to North Korea. Is there a military option, Senator?

BLUMENTHAL: There's no good military option. There's no palatable military option that involves small costs in human terms or even financial terms. And that's why we need to enforce these sanctions, commit and invest whatever it takes to enforce these sanctions vigorously and make them stick. Because the secretary of state has said we'll monitor and then we'll have conversations. What's needed is a proactive approach.

BLITZER: Well, do you think the U.S. right now should negotiate with North Korea, if the North Koreans won't even put the issue of nuclear weapons or ballistic missiles on the table?

BLUMENTHAL: We should negotiate when the North Koreans evidence that they're serious about those negotiations, and they may not be serious until we enforce these sanctions vigorously. And there is a lot of sentiment on the Armed Services Committee where I sit that there is no good military option. And so we have to use these sanctions, which were passed unanimously, by the Security Council. They reflect the world opinion that's represented there. And we have to reach out to the world community and unite them, just as we did in bringing Iran to the table, where it worked.

BLITZER: Senator Blumenthal, thanks for joining us.

BLUMENTHAL: Thank you, Wolf.

BLITZER: Coming up, Vice President Mike Pence slams a report that says he's considering a White House run in 2020. Why is his denial so forceful?

(COMMERCIAL BREAK)

BLITZER: resident Trump may be on vacation, but he's not taking a break from Twitter, lashing out with a series of attacks on a top Democratic senator.

[17:34:03] Let's dig deeper with our correspondents and our specialists. And Chris Cillizza, the first series of tweets on Senator Blumenthal from the president earlier this morning. "Interesting to watch Senator Blumenthal of Connecticut talking about hoax Russian collusion when he was a phony Vietnam con artist. Never in U.S. history has anyone lied or defrauded voters like Senator Richard Blumenthal. Told stories about his Vietnam battles and conquests, how brave he was, and it was all a lie. He cried like a baby, begged for forgiveness like a child. Now he judge collusion." And just moments before we went on the air, "I think Senator Blumenthal should take a nice long vacation in Vietnam, where he lied about his service, so he could at least say he was there."

There's something personal. Senator Blumenthal, I asked him about this, why the president keeps going after him when there are so many other Democratic senators and representatives who go after him. But there's something personal in their history that drives the president to launch these attacks.

CHRIS CILLIZZA, CNN POLITICS CORRESPONDENT AND EDITOR AT LARGE: I think there might be, because he doesn't attack -- I mean, he does attack other senators, but he doesn't do it in such personal terms as he does with Blumenthal.

I do think -- you mentioned this in your interview with him. I do think the fact that Blumenthal's family and his wife's family is tied up in ownership of the Empire State Building. Obviously, Trump had an interest in that. I think it comes before them and is long-running. We may never learn the answer.

But a couple things. Donald Trump proving yet again that he is not only incapable of taking the high road; he appears to be unaware where that road begins.

No. 2, in Trump's defense, Richard Blumenthal -- I covered this campaign -- Richard Blumenthal did -- there was a story in "The New York Times" that came out that detailed a series of exaggerations that he made -- this was the 2010 campaign -- serious exaggerations he made about Vietnam. He repeatedly had said that he had been there, and "When we were in Vietnam," and he never had actually been to the country.

So factually it's right. It's hard to know, because Senator Blumenthal wouldn't engage, and I don't know that Donald Trump would engage. It's hard to know if there's anything beyond just that fact. Lots of politicians exaggerate their resumes. This is not unique to Richard Blumenthal.

But it does feel personal, in a way, that sometimes his attacks on other people, like "Lisa Murkowski should have been with us." I'm sure that didn't make Lisa Murkowski happy, as Dana detailed in her conversation with her, but it doesn't have that sort of personal, raw emotional feel that these tweets do.

BLITZER: Senator Blumenthal did apologize for all the statements that he had made about serving in Vietnam, as opposed to during the Vietnam War. He did serve six years in the U.S. Marine Corps Reserves, but he never went to Vietnam. He apologized for that and said he shouldn't have done it He was still elected to the U.S. Senate by the people of Connecticut.

DANA BASH, CNN CHIEF POLITICAL CORRESPONDENT: And the president, who's about the same age, got several deferments and never even, you know, got that far. Regardless of that, the bigger issue here is the president continuing

to tweet all day and chief of staff is praying for sunny weather tomorrow so we can actually get on the golf course and not be stuck inside in the rain where he had -- you counted, what...

BLITZER: Thirteen.

BASH: ... 13 tweets today.

CILLIZZA: Although it's -- I haven't looked at my phone in the last two minutes.

BASH: Which is fine. That's his mode of communication. If he's going to do it constructively. But most of his tweets were not constructive. It was, first of all, misinformed, saying that the media are not covering the North Korea story, the resolution at the U.N. over the weekend, U.N. Security Council, which imposed more sanctions on North Korea, which was a big political win for this administration, because they got China, especially, and also Russia on board. We covered that -- I mean, I worked this weekend. We covered it real time. Nikki Haley, who's on U.N. security -- U.N. ambassador, was on CNN for a live interview.

So some of it is just unclear where it's coming from, wanting to change the subject. But some of the subject-changing steps on the message that he wants to get out, which is not unusual for this White House.

BLITZER: He's going after Democrats, Democratic Senator Blumenthal in this particular case, not going necessarily -- and the news media, but he's not going against his fellow Republicans.

MARK PRESTON, CNN POLITICAL ANALYST: Right. It's a very low bar, I think, that we're like, "Wow, it's a great day," you know, if he hasn't attacked someone from his own party.

You know, I think his -- his use of Twitter today is a perfect example of how you do not use Twitter. He has 35 million followers on Twitter. I mean, even if a tenth of them were able to see his tweets, should he not use that medium to try to get his policy goals done, whether that is to try to get tax reform done?

Maybe he should have used Twitter in a more strategic way during the health care vote to try to get people, to try to convince those like Lisa Murkowski or Susan Collins or John McCain to support the health care bill. But instead he uses it as a tool, maybe as a weapon -- I guess is a better way to use it -- against those he doesn't like.

Clearly, what he did with Blumenthal right now, he's trying to attack the senator's credibility. And whether that works or not, we'll see.

CILLIZZA: And politically speaking, I mean, this is the other thing Mark's right about. There's no political strategy here. Dick Blumenthal is going to be reelected in Connecticut for as long as he wants.

BASH: He just was.

CILLIZZA: And I'm from Connecticut. Trust me. He's going to be fine there. It's not as though he's picking -- let's say he picked Heidi Heitkamp in North Dakota or Joe Donnelly in Indiana, someone who's up in 2018 and say, "This people did X, Y or Z." Those people have real political vulnerability.

Dick Blumenthal, this is -- this is Donald Trump entertaining his own sort of flights of fancy.

BASH: And at the end of the day, this is not a partisan witch hunt. This is a special counsel investigation going on by somebody -- led by somebody who is not a Democrat -- Robert Mueller is not a Democrat -- appointed by somebody who is not a partisan. If anything, it's the partisan in the president's favor, because he was appointed by the deputy attorney general, who is President Trump's deputy attorney general.

[17:40:04] BLITZER: And he was nominated by President Trump himself.

BASH: Precisely.

BLITZER: And Rosenstein himself said this weekend this is not a fishing expedition.

BASH: Exactly.

BLITZER: This is a legitimate investigation.

Everybody stick around. There's much more. We're getting more information into THE SITUATION ROOM. We'll be right back.

(COMMERCIAL BREAK)

BLITZER: Vice President Mike Pence is vehemently denying a report that he's eyeing a possible run for the White House in 2020 if President Trump doesn't run. The article in the "New York Times," Chris, mentioned several other Republicans were looking ahead to 2020: Ben Sasse, Tom Cotton, John Kasich. The story also mentioned the vice president looking ahead. The vice president issued a strong statement slamming the report. Today's article in the "New York Times" is disgraceful and offensive to me, my family, and our entire team. My entire team will continue to focus all our efforts to advance the President's agenda and see him re-elected in 2020. Any suggestion otherwise is both laughable and absurd.

What do you think of that? That's his final --

CHRIS CILLIZZA, CNN POLITICS EDITOR-AT-LARGE: That statement was about as long as the entire "New York Times" story. I think that Mike Pence understands that his wagon is hitched to Donald Trump, and that the -- his path to presidency is the path most vice presidents take. Two-term president, you run as the logical heir to that.

Any break is problematic -- any break between Trump and Pence then, even a perceived one, is problematic, more so because he's dealing with Donald Trump, which he knows Donald Trump does not like, more than anything, any one star shining brighter than his own. That's why I think you saw him come out so forcefully so that if Trump saw the story, he immediately saw the Pence denial as well.

BLITZER: You know the President saw the story because he reads the "New York Times." He's very much interested in what the "New York Times" is saying about him and his team.

DANA BASH, CNN CHIEF POLITICAL CORRESPONDENT: That's right. He's very interested in the economic stability of the "New York Times," so he wants to make sure to keep reading it.

Yes, of course, there's no question that he saw it. Just kind of going back in through the timeline of what happened with story and the Pence team now over the weekend, the fact that he put out -- he, the Vice President, put out this strongly worded official statement is so unusual.

CILLIZZA: Yes.

BASH: I mean, we probably should underscore that, so unusual. And then to subsequently have his Press Secretary -- the Vice President's Press Secretary was on T.V. all day today and kind of rapid fire radio, television, pushing back incredibly hard on the notion that the Vice President is, at all, trying to, you know, build up his own brand, build up his own base, if you will, in the off chance that the President, for whatever reason, can't run in 2020.

You know, the question is, why didn't they just keep it simple? Why didn't they keep it the way somebody said over the weekend -- I think it was Kellyanne Conway, she said it on ABC -- is, of course, he's doing all of this. He's doing all of this because he's doing it for the Trump-Pence team. That's what vice presidents do. They kind of play to their own strength to help the team.

And the truth is, Mike Pence is somebody who has relationships with the Republican donors because he has needed them since he's been, you know, in this state politics, never mind up through the governors' race, and the President didn't need them.

BLITZER: Mark?

MARK PRESTON, CNN SENIOR POLITICAL ANALYST: You know, a couple things. One is the "New York Times" story never says that Mike Pence was being disloyal to the President, right?

CILLIZZA: That's right.

PRESTON: He has been his biggest cheerleader. He has carried all his water. When you see Mike Pence out doing these fundraising events, which I think is smart on his part --

BASH: Yes, definitely.

PRESTON: -- it would be political malpractice for not to be prepared to be able to step into the role of running for president. That statement was a statement directly to President Trump. I mean, that's what it was. That wasn't, you know, to the American people.

Moving forward now, though, I bet you, you will see Mike Pence be a little bit more careful in what his aides might say to donors. But the fact of the matter is he is prepared to run in 2020 if he needs to be, but he's also going to be right at Donald Trump's side.

[17:53:24] BLITZER: Welcome back. You know, Dana and company, there's two presidents on vacation right now.

(LAUGHTER)

BLITZER: Two presidents on vacation.

CILLIZZA: And company.

BLITZER: The President Trump is on vacation in New Jersey. President Putin of Russia, he's on vacation in Siberia right now. And all of a sudden they're releasing -- you can see he is fishing. He is swimming. He is showing a lot of himself, shall we say --

CILLIZZA: It's amazing.

BLITZER: -- in all the video that is being released. This president, is he sending a message --

BASH: Yes --

BLITZER: -- to the other president?

BASH: He is sending a message.

(LAUGHTER)

BASH: I mean, I'm not sure exactly who the message is to, maybe just the world. I mean, I think it's harder to find pictures of Vladimir Putin with his shirt on than it is with his shirt off.

But it just makes me think of a story that George W. Bush used to tell about the first time he met Vladimir Putin, and Putin was obsessed with showing the President, then, Bush how big his dog was because President Bush had a little dog. So I think the point is imagery is everything for this guy, and that shows you.

BLITZER: Not the first time we've seen Putin shirtless.

CILLIZZA: No. As Dana said, he is shirtless as much as he's shirted. Two things, one, I never knew southern Siberia was nice. If you said, I'm going on vacation in southern Siberia, I'd be like, that doesn't sound good.

PRESTON: You ain't coming back. CILLIZZA: Number two, in the first pictures we showed -- there's one.

PRESTON: All right. Well, I'm just going to have to take off my shirt.

(LAUGHTER)

PRESTON: Listen, I would --

CILLIZZA: Maybe he's boost.

PRESTON: If the question was -- if the question is, would you rather be with him in Siberia or with Donald Trump in Bedminster? I like to play golf, and I think I would probably rather be with Donald Trump.

BLITZER: No, he loves New Jersey. He was just kidding around. All right, guys, everybody stick around.

There is more important news we're following, including some new online attacks by President Trump on a top Democratic senator. Tonight, his Twitter storm is still raging.

(COMMERCIAL BREAK)

[17:59:56] BLITZER: Happening now. Vowing revenge. North Korea goes ballistic over new U.N. sanctions for its missile test. Kim Jong-un's regime blaming the United States and warning of nuclear war. Can a military conflict be avoided?